I would throw in another vote for the Simpson Chubby 2 Synthetic. For the Classic Faux Ivory you are under $100, and just a fantastic brush. It is possibly the first one I have considered a duplicate of, just a handle change.
I have to second the Stirling Kong recommendation. I recently obtained one after reading numerous recommendations from folks on this forum. It exceeds the hype, IMO.
Yeah they sell out fairly quickly. This one is available with the same knot. Same diameter, just a slightly shorter loft. https://www.stirlingsoap.com/synthetic-shave-brush-26mm-x-54mm/